DNA microarray for forensic intelligence purposes: High-density SNP profiles obtained directly from casework-like...

SNP analyses from a forensic intelligence perspective have proven to be an important tool to restrict the number of suspected offenders and find missing persons. DNA microarray assays have been demonstrated as a potential feature in forensic analysis, like such as forensic genetic genealogy. The objective of this study was to describe the results from DNA microarray assay from saliva samples deposited on a glass surface collected from by a double swab technique, commonly applied in crime scenes. Eighteen samples from the same person were subjected to Infinium® Global Screening Array-24 v1.0 (~642.824 SNP markers) in two different protocols - with or without the DNA purification procedure. The measured genotype was compared with a Consensus Genotype, obtained from standard control samples, and the parameters such as Call Rate and GenCall Scores were evaluated. Results showed that the Call Rate parameter is enough to estimate the probability of obtaining a correct genotype in the SNP assay. Reliable genotypes with a confidence level of more than 90% (at least 90.15%) were observed in Call Rates above 69.41%, regardless of the experimental condition. Our data demonstrate that DNA Microarray from samples collected under conditions such as those found at crime scenes can generate high-density SNP genetic profiles with a confidence level greater than 90%. Enzymatic adjustments and protocol changes may enable DNA microarray assays for crime analysis and investigation purposes eliminating the purification step in the future. Our data suggest that DNA microarray can support criminal investigation teams from a forensic intelligence perspective.